Method of drying coated wires

ABSTRACT

Adjacent wires passing through drying oven after being coated with liquid enamel are run at different speeds to prevent wires from sticking together while curing.

' United States Patent 191 Callan 118/68 X under Nov. 19, 1974 [54]METHOD OF DRYING COATED WIRES 1,485,254 2/1924 Dickie 34/154 UX2,434,169 1 1948 L 341 4 [75] Inventor: Bernd Linder, Hendersonvrlle,N.C. 2,583,427 111952 I 2 9 2,994,624 8/196l. Lit et a1. 117/232 .[73]Asslgnee' General Electnc Comm"), 3,686,772 8/1972 Drummond 34/154 [22]Filed: May 22, 1972 ['21] Appl' 255792 Primary Examiner-Harry J.Gwinnell Attorney, Agent, or Firm-Sidney Greenberg [52] US. Cl .L-.34/25, 34/52, 34/154, l17/119.6, 1l7/128.4, 117/232, 118/68, l18/DIG. 22[51] Int. Cl. F26b 3/22, B44d l/42 [57] ABSTRACT [58] Field of Search34/25, 52, 154; 117/119.6,

ll7/128.4, 232, 119.8; 118/68, DIG, 19, Adjacent wires passing throughdrying oven after DIG. l8, DIG. 20, D10. 22, 67, 405 being coated withliquid enamel are run at different speeds to prevent wires from stickingtogether while [56] References Cited curing.

UNITED STATES PATENTS 1 894,592 7/1908 4 Claims, 2 Drawing Figy resMETHOD OF DRYING COATED WIRES The present invention relates to apparatusfor applying coating compositions such as enamels, varnishes, lacquersand the like to elongated articles such as wire.

More particularly, the invention is concerned with an apparatus andmethod for handling multiple strands of coated wire passing through adrying oven.

It is an object of the invention to avoid the difficulties, includingscrap waste and loss of productivity, attendant on the sticking togetherof adjacent coated wire strands passing through a drying oven.

It is a further object of the invention to provide for an increase inthe number of coated wire strands which can be simultaneously treated ina drying oven while avoiding the above-described difficulties.

Specific objects of the invention are to provide an apparatus and amethod for preventing coated wire strands from sticking together duringthe process for drying and curing the wire coating.

Other objects and advantages will become apparent from the followingdescription and the appended claims.

With the above objects in view, the present invention in one of itsaspects relates to wire coating apparatus comprising, in combination,coating means for applying hardenable liquid coating material on aplurality of wire strands, drying means for drying the coated strandsfor hardening the coating thereon, means for passing a plurality ofcoated wire strands adjacent one another through the drying means, andmeans forimparting relative motion between adjacent ones of theplurality of coated wire strands while passing through the drying meansfor preventing sticking of adjacent wire strands together.

The invention will be better understood from the following descriptiontaken in conjunction with the accompanying drawing, in which:

FIG. 1 is a perspective, somewhat diagrammatic view, of a wire coatingapparatus embodying the present invention; and v I FIG. 2 shows amodification of the apparatus shown in FIG. 1.

Referring now to the drawing, and particularly to FIG. 1, there is shownan apparatus for coating a plurality of wires with liquid insulatingenamel and hardening by heat the thus applied coatings. For thispurpose, there is provided a lower set of grooved guide sheaves l forrespectively receiving a plurality of wires 2, 3, 4 and 5 from pay-offsupply reels (not'shown) and independently guiding the wires upwardlyinto vessel 6 containing a supply 7 of resinous viscous varnish (such aspolyvinyl formal or polyester imide composition) to be applied to thewires. The wires are typically of copper or aluminum, but may be ofvarious other types of metals or materials, and the enameling materialmay be of various other types of hardenable liquid coating composition.After emerging from wire coating vessel 6, the

' wires pass through wire coating dies 8 (shown in exaggerated scale)for removing excess liquid coating material therefrom, and the wirespass upwardly in closely adjacent arrangement through baking or dryingoven .9 of any suitable or conventional type wherein the applied enamelcoating is heat-hardened. Thereafter, the

wires pass around a set of independent upper guide.

sheaves 10 as they leave the top of oven 9..

In a typical embodiment of the invention, alternate wires 2 and 4 arethicker in diameter than wires 3 and 5, shown in interrupted lines forclarity, and in accordance with the invention the thinner wires 3 and 5are passed through oven 9 at a greater speed than wires 2 and 4. As aresult of thus providing for relative motion between the adjacent wirestrands, the coated strands will not stick to one another during theprocess of drying in oven 9, even though the wire strands may come intocontact with one another while passing through the oven.

For this purpose there is provided in the illustrated embodiment a setof guide sheaves 11 for transporting the thinner wires 3, 5 to a firstdriving roller 12 driven by motor 13 and another set of guide sheaves 15for transporting the thicker wires 2, 4 to a second driving roller 16driven by motor 17 at a slower speed than roller 12 is driven by motor13, the wires being directed from the respective driving rollers tosuitable take-up reels or other storage means (not shown). Since itrequires less time to cure the coating on the thinner wires than on thethicker wires, inasmuch as there is less mass of coating on the thinnerwires, effective drying and hardening of the coating on the latter wiresare achieved despite their faster passage through the oven.

In a typical procedure, the thinner wires 3, 5 having, say, a 42 mildiameter may be run at a speed of feet/- minute, while the thicker wires2, 4, which are typically of 50 mil diameter, may be run at 50feet/minute.

While only four wire strands are shown for purposes of illustration, itwill be understood that in practice a considerably larger number of wirestrands will be run side by side with a similar arrangement of thinnerwires interspaced between the thicker wires. It has been found that aspacing of as little as 7/16 inch or less between wire strands can beemployed in practicing the invention while still obtaining satisfactoryresults.

It will also be understood that all the wires may be of the same size ifdesired, and the alternate wires can be run at slightly different speedsto obtain the benefits of the invention without adversely affecting thecuring of the coatings thereon. It has been found, in fact, that in sucha case, a speed difference of as little as 5 feet/minute is adequate toprovide satisfactory results.

By virtue of the described invention, it is possible to arrange thecoated wires closer together than heretofore without encountering thedifficulty of the wires sticking together, and thus enable moreeffective use of existing oven capacity or permit the use of smallersize ovens. Moreover, the invention makes it possible to use taller wiretowers with longer unsupported wire spans, which in prior wire coatingapparatus increased the risk of adjacent wire strands coming intocontact and sticking to one another. This advantage afforded by theinvention is particularly significant in the use of aluminum wire, whichusually cannot withstand the higher tension (such as is possible withcopper wires) required to keep the wire strands separated in theirpassage through the drying oven, and which therefore must be run withgreater slack. FIG. 2 shows a different embodiment of the driving meanswhich may be used to run the alternate wires at different speeds withoutthe use of separate drive rollers and motors. As shown, a single driveroller 20 having large diameter sheave portions 20a and small diametersheave portions 20b alternately formed thereon for receiving and drivingall of is rotated by motor 21.

While the present invention has been described with reference toparticular embodiments thereof, it will be understood that numerousmodifications may be made by those skilled in the art without actuallydeparting from the scope of the invention. Therefore, the appendedclaims are intended to cover all such equivalent variations as comewithin the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. in a method of treating coated wires wherein a plurality of wirestrands coated with heat hardenable coating material are passed closelyadjacent one another in thesame direction through a drying oven for heathardening the coating material, the improvement which comprises the stepof imparting relative longitudinal motion between adjacent ones, of saidplurality of coated wire strands during passage through said drying ovenfor preventing them from sticking together.

2. A method as defined in claim 1, wherein said step comprises movingadjacent ones of said coated wire strands at different speeds.

3. A method as defined in claim 2, wherein alternate ones of said wirestrands are thinner than the adjacent wire strands and are moved at afaster speed than said adjacent wire strands.

4. A method as defined in claim 1, wherein said step comprises movingalternate ones of said plurality of coated wire strands at apredetermined speed, while moving the remaining coated wire strands at adifferent predetermined speed.

1. In a method of treating coated wires wherein a plurality of wirestrands coated with heat hardenable coating material are passed closelyadjacent one another in the same direction through a drying oven forheat hardening the coating material, the improvement which comprises thestep of imparting relative longitudinal motion between adjacent ones ofsaid plurality of coated wire strands during passage through said dryingoven for preventing them from sticking together.
 2. A method as definedin claim 1, wherein said step comprises moving adjacent ones of saidcoated wire strands at different speeds.
 3. A method as defined in claim2, wherein alternate ones of said wire strands are thinner than theadjacent wire strands and are moved at a faster speed than said adjacentwire strands.
 4. A method as defined in claim 1, wherein said stepcomprises moving alternate ones of said plurality of coated wire strandsat a predetermined speed, while moving the remaining coated wire strandsat a different predetermined speed.